Buttocks pain, pulsating sensation, large mass in ovary, cancer causing risk. What can be done?

i started having pain on lower side of right buttock about 2 wks ago. It is very uncomfortable to walk, sit. It feels like when u sit on a hard surface for a long period of time.. At times it throbs/pulsates and VERY painful, then just a constant uncomfortable pain. When I try to find the area that the pain is in, all I feel is the bone. It is hard to pinpoint exactly where it is.. I just need to see if I can get some answers or possiblities of what it might be... as a footnote, last August, they found a large mass in my left ovary, It was high risk of being cancerous at that time. When they removed it, I had abnormal cells, on the border.. the biopsy showed no cancer thank goodness...
I do work 5 days a wk. standing and walking.... if you can help, i would appreciate it. thank you.
Lynda